dependency on tkinter

[cwmeijer]

When tests after pip install mcfly on a new ubuntu docker image, I get 'ImportError (No module named _tkinter, please install the python-tk package)' apt install python-tk solves the issue. The dependency is only needed for the tutorial because it is a matplotlib dependency. We could solve this by creating a separate repo for the tutorial. This way the matplotlib dependency can be removed from mcfly altogether.

[dafnevk]

In the find_architecture module we have a function to plot the training process. If we want to keep that functionality, we also need to keep the matplotlib dependency.

[dafnevk]

I removed the plotting function, since we have the javascript visualization for plotting the training process. The matplotlib dependency is thus no longer necessary.